The invention relates to a charging rack for receiving shaped bodies made of ceramic and glass-ceramic materials, which are baked in a furnace, particularly in a roller-type furnace, whereby the charging rack has the shape of a grid and consists of a frame assembled from a plurality of parts, as well as a plurality of supporting parts, and whereby the parts of the charging rack are manufactured from refractory materials.
Ceramic materials comprise raw materials containing clay minerals and are processed to ceramic articles (e.g. crockery; sanitary ceramics; construction ceramics) by shaping at room temperature and subsequent baking. Glass-ceramic materials comprise glasses which, following shaping and a subsequent heat treatment, are processed to glass-ceramic articles. Partly controlled devitrification occurs in the course of the thermal treatment due to partial crystallization. The baking or heat treatment of ceramic and glass-ceramic materials is carried out at temperatures of 800.degree. to 2000.degree. C., preferably at 1000.degree. to 1400.degree. C., in furnaces which are operated both in batch and continuous operations. The articles shaped from ceramic or glass-ceramic materials are, in many cases, arranged on charging racks, which are then loaded in the furnace, and removed from the latter after the baking process has been completed. Such charging racks have been successfully used especially in continuous furnace operations, which are preferably carried out in roller-type furnaces, because such racks protect the shaped bodies against damage as the latter are being passed through the furnace, and facilitate the handling of the shaped articles.
Known charging racks preferably comprise ceramic materials such as, for example cordierite or mullite, and have the shape of boards. Such charging racks have to be heated and cooled gradually because of their low thermoshock stability. The continuous operation of the baking process is prolonged in a disadvantageous way due to said material property. The known charging racks, which are manufactured from conventional metals, have a low resistance to corrosion and low high-temperature stability, which has an adverse effect on their useful life. Furthermore, owing to their low high-temperature stability, the charging racks made of conventional metallic materials are required to have a high structural weight, which negatively affects the energy household of the baking furnace.